In the 1st U19, we established panels of high specificity and high affinity monoclonal antibodies against the following human DC receptors: LOX-1, BDCA-2, DC-SIGN/L, Dectin-1, CD1d, DC-ASGPR, Langerin, CLEC-6, MARCO, CD40 and DCIR. These human DC receptor reagents uncovered fundamental new biology and were used for development of prototype vaccines that target antigens directly to DCs. Based on extensive efficacy data in vitro, as well as preliminary studies in two in vivo models, the Humouse and Rhesus macaque, we hypothesize that the most potent antigen-targeting vaccines will deliver multiple antigens, engage two receptors simultaneously, and will be directly linked to adjuvants. We envision three areas for improvement that are the basis of Aims 1-3. In Aim 1, we will construct polyvalent vaccines composed of influenza viral hemagglutinin (HA), nucleoprotein (NP), and matrix protein2 (M2). Triple vaccines will induce broad repertoires of both cellular and humoral immune responses. In Aim 2, we will generate vaccines that target two DC receptors to enhance the immunogenicity of vaccines. In Aim 3, adjuvant-linked DC-targeting vaccines will be produced. The vaccines generated herein will undergo analysis of DC binding, activation, and internalization through Aim 4, and then undergo further studies within Projects 1-4. Projects 1 and 2 serve, through in vitro analysis, to discover the most potent candidate vaccines - particularly those that will evoke mucosal immunity. The selected vaccines will be tested thoroughly in vivo via Projects 3 and 4.